When was the last time you were tested? Not just for STIs, but for HIV? If the answer is, "Um, never..." or "IDK a while ago," consider why you haven't been tested more recently. Is it because you think you haven't been exposed to HIV? Or maybe because you're pretty sure you'd know if you had HIV?

The truth is that HIV can affect anyone, and you won't know your status until you get tested. So why aren't young people getting tested for HIV?

Outside of donating blood, 38.8 percent of women and 53.8 percent of men reported never having been tested for HIV, according to a startling new study from the CDC. For younger people (ages 15 to 24), those numbers are even higher: 63.9 percent of women and 73.7 percent of men said they had never been tested. The study was published last week in the CDC's National Health Statistics Reports and was based on nationally representative data on HIV testing among women and men aged 15 to 44 from the 2011–2015 National Survey of Family Growth (NSFG). The NSFG also asked why people had never been tested for HIV. The most common response was that they were “unlikely to have been exposed to HIV,” followed by the response that they had “never been offered an HIV test.”

The even scarier part: These findings fly in the face of the CDC recommendations that everyone be tested for HIV at least once in their lifetime, and that many people get tested more frequently based on certain (not entirely uncommon) risk factors.

The fact that younger people are the least likely to get tested is especially alarming because people aged 13 to 24 accounted for 22 percent of all new HIV diagnoses in the U.S. in 2015. And according to research from the CDC, the highest rates of undiagnosed HIV in 2014 (among men who have sex with men) occurred in this same age group.

The only way to know your status is to get tested—which is why the CDC recommends that everyone between the ages of 13 and 64 get tested for HIV at least once as part of routine health care.

As we mentioned, people with certain risk factors should get tested more often than that. If you tested negative for HIV more than one year ago, you should get re-tested as soon as possible if you have one or more risk factors. That includes being a man who has had sex with another man, having sex (anal or vaginal) with an HIV-positive partner, having more than one sexual partner since your last HIV test, having exchanged sex for drugs or money, being diagnosed with or treated for another sexually transmitted disease, being diagnosed with or treated for hepatitis or tuberculosis, or having sex with someone whose sexual history you don’t know. It also includes injecting drugs and sharing needles. If any of the above applies to you or someone you've had sex with since your last HIV test, you should get tested again.

And if any of those risk factors continue to apply to you, you should be tested at least once a year, the CDC advises. Sexually active gay and bisexual men may need to be tested even more frequently. The CDC also recommends talking about your sexual and drug use history with a new partner before having sex for the first time, and considering getting tested for HIV in between sexual partners.

“The new report is critical to understanding why we are not being successful in getting adults tested for HIV,” Sharon Nachman, M.D., division chief of pediatric infectious diseases at Stony Brook Medicine and Chair of the NIH-funded maternal child HIV network (IMPAACT), tells SELF.

“Is it where we test? Is it how we test? Is it who we offer testing to? Is it the messaging that we have around HIV—that ‘you might not be at risk’? In fact, it is all of these," she says. "We need to do a better job messaging the HIV risk to everyone. Even if you think your risk is low, it’s still real, and you should get tested.”

So how does HIV testing become more accessible to all?

Dr. Nachman, who was not involved in the new CDC report, believes the key is making people feel more comfortable taking the test and making the test cheaper, especially ones people can take at home. (Walmart’s cheapest FDA-approved home HIV test is $37.99 for a single test.) “Fixing one of these things alone won’t be enough,” she says. “It has to be a part of routine care for all—not something special that you do for ‘those populations’ but rather something you do for everyone.”

The CDC estimates that of the 1.1 million people living with HIV in the U.S., one in seven of them don’t know their diagnosis. “It’s clear that more work needs to be done to increase the percentage of those who know they are infected and thus can access care,” Sherry Deren, Ph.D., co-director of the Center for Drug Use and HIV/HCV Research at the NYU Rory Meyers College of Nursing, tells SELF. “On the individual level, expanded educational efforts, including in schools, can help make individuals aware of the need for HIV testing, the possibilities of transmission even if partners look healthy, and the availability of effective treatment.”

If you’ve never been tested for HIV, or think you need to be re-tested, your first step is to speak to a health care provider. HIV screening is covered by health insurance without a co-pay under the Affordable Care Act, but if you don’t have insurance, some testing sites, such as community health centers, may offer free tests. Other testing locations include medical clinics, substance abuse programs, and hospitals. You can find a testing site near you by calling 1-800-CDC-INFO (232-4636), visiting gettested.cdc.gov or texting your ZIP code to KNOW IT (566948).